[HTC Sensation] Boozezela:
I forgot to mention:

When the screen is OFF, skipping tracks with a volume +/- long press works only the first couple of times.

Then music will stop (default HTC music player). If you turn the screen on by pressing the power button, the track may actually skip and the music may actually resume playing.

This also happened on Blitz 3.9, not only on 4.0.

So there is a backup CID set and your keycaps is QWERTY already.

You can try to change the backup CID to something else and see what happens.

You need to flash the 1.17 ENG HBOOT (link is somewhere on XDA), this will give you access to a lot more commands.

fastboot oem h

(bootloader) command list
(bootloader) mb
(bootloader) mh
(bootloader) mw
(bootloader) ew
(bootloader) eh
(bootloader) eb
(bootloader) mmu
(bootloader) ram_test
(bootloader) jump
(bootloader) test
(bootloader) sdtest
(bootloader) eraseconfig
(bootloader) writeconfig
(bootloader) readconfig
(bootloader) writesku
(bootloader) readsku
(bootloader) rflash
(bootloader) tflash
(bootloader) block_test
(bootloader) partition_test
(bootloader) rbchk
(bootloader) erasesd
(bootloader) btrouter
(bootloader) tick
(bootloader) heaptable
(bootloader) emapi
(bootloader) emapiTest
(bootloader) emapiCountryID
(bootloader) emapiWlanMac
(bootloader) emapiSetDefCal
(bootloader) emapiReadCal
(bootloader) lr
(bootloader) imgcrc
(bootloader) resetautoimage
(bootloader) resetpreferdiag
(bootloader) resetRUUflag
(bootloader) writeserialno
(bootloader) readserialno
(bootloader) battcheck
(bootloader) enter
(bootloader) gotofastboot
(bootloader) gotohboot
(bootloader) writemid
(bootloader) usbtestmode
(bootloader) eraseWifiFlash
(bootloader) erase
(bootloader) readmbserialno
(bootloader) listpartition
[B][COLOR="Red"](bootloader) erasebcid
(bootloader) writebcid
(bootloader) readbcid[/COLOR][/B]
(bootloader) fmrouter
(bootloader) fmtx
(bootloader) resetuP
(bootloader) bdaddress
(bootloader) wMfgTp
(bootloader) rMfgTp
(bootloader) emptypagecheck
(bootloader) saveprt2sd
(bootloader) savemem2sd
(bootloader) savefb2sd
(bootloader) emapiInit
(bootloader) emapiChannel
(bootloader) emapiBand
(bootloader) emapiRate
(bootloader) emapiRateset
(bootloader) emapiCountry
(bootloader) emapiTXpwr1
(bootloader) emapiPkteng_start
(bootloader) emapiPkteng_stop
(bootloader) emapiOut
(bootloader) emapiFqacurcy
(bootloader) emapiCrsuprs
(bootloader) emapiUp
(bootloader) emapiDown
(bootloader) emapiMpc
(bootloader) emapiCounters
(bootloader) emapiVersion
(bootloader) emapiEtheraddr
(bootloader) emapinRate
(bootloader) emapiSetIrqPin
(bootloader) bkflash2emmc
(bootloader) fl
(bootloader) loaddiag
(bootloader) lnb
(bootloader) init_a1026_fw
(bootloader) checkKeyCard
(bootloader) usbspeed
(bootloader) ats
(bootloader) gpiow
(bootloader) gpior
(bootloader) mddiw
(bootloader) mddir
(bootloader) clock
(bootloader) i2cr
(bootloader) i2cw
(bootloader) i2ctest
(bootloader) ulpi
(bootloader) changeCid
(bootloader) read_l2_acc_fuse
(bootloader) qupi2cr
(bootloader) qupi2cw
(bootloader) pmgpiow
(bootloader) pmgpior
(bootloader) dgtest
(bootloader) entpa2051
(bootloader) bumpclk
(bootloader) switch_ddrfeq
(bootloader) ntrigsetcal
(bootloader) ltetest
(bootloader) sdio_loopback
(bootloader) sdio_setsize
(bootloader) sdio_readblk
(bootloader) sdio_writeblk
(bootloader) sdio_readblk
(bootloader) sdio_dumpreg
(bootloader) emmc_boot
(bootloader) fdisk_emmc
(bootloader) set_partition_emmc
(bootloader) erase_emmc
(bootloader) test_emmc
(bootloader) sector_erase_emmc
(bootloader) fat_format_emmc
(bootloader) init_emmc
(bootloader) reinit_emmc
(bootloader) write_mmc
(bootloader) set_wp_emmc
(bootloader) write_prot_test
(bootloader) clear_wp_emmc
(bootloader) set_enh_area_emmc
(bootloader) get_identifier_token
(bootloader) keytest
(bootloader) heap
(bootloader) boot
(bootloader) reset
(bootloader) powerdown
(bootloader) rebootRUU
(bootloader) heap_test
(bootloader) rtask
(bootloader) task
(bootloader) enableqxdm
(bootloader) gencheckpt
(bootloader) lock
(bootloader) list_partition_emmc
(bootloader) load_emmc
(bootloader) check_emmc
(bootloader) check_emmc_mid
(bootloader) read_mmc
(bootloader) get_wp_info_emmc
(bootloader) send_wp_info_emmc
(bootloader) get_ext_csd_emmc
(bootloader) get_sector_info_emmc
OKAY [ 0.152s]
finished. total time: 0.152s

Then could try to erase the backup CID with "fastboot oem erasebcid" or change it to HTC__001 like I did with "fastboot oem writebcid HTC__001" (probably safest) and see if with an international CID the keyboard will stay in QWERTY.

In any case DO NOT DISCONNECT THE PHONE until you see the dos prompt again.

Note that the 1.17 HBOOT is not compatible with ICS and JB, and the phone will bootloop. This means that you will have to flash 1.27.1111 back.

There is also the changeCid command that will NOT affect the backup CID, but that seem to change the CID in a deeper level, as it touches more things and needs 20-30 seconds to complete.